Audion or lamp relay or amplifying apparatus



M. c. A. LATOUR. AUDION 0R LAMP RELAY 0R AMP L I FYING APPARATUS.

APPLICATION HLED DEC. 28, 1917- Patented Feb. 7, 1922.

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/x M PW Attorney.

M. C. A. LATOUR. AUDION 0R LAMP RELAY 0R AMPLIFYING APPARATUS.

APPLICATION FILED DEC-28,1917.

1,405,523. r Patented Feb. 7, 1922.

2 SHEETSSHEET 2.

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tion.

PATENT OFFICE.

IABI'US C. A. LA'I'OUB, OI I PABIS, FRANCE- LUDIOIT OB LAX? RELAY OR mrnmmd APPARATUS.

Specification of Letters Patent.

Patented Feb. '7, 1922.

Application filed December 28, 1917. Serial Roi 209388.

To all whom it may concern:

Be it known that I, Mama's a citizen of the Republic of France, residing at Paris', 10 Rue Auber, France, have invented certain new and useful lmprove ments in or Relati to Audion or Lamp Relays or Am lifylng Apparatus, (for which I have filhd applications in France April 15', 1916, and England April 16, 1917,) of which the followlng is a specifica- This invention relates to audions or thermionic rela s or amplifiers foruse vfor example in wire ess telegraphy and telephony.

The object of the present invention is, to determine the conditions of construction of the transformers utilized in these amplifiers for the urpose of obtaining the maximum relay efl ect given by the lamps; also to indicate the precautions to be taken in order to obviate objectionable noises. a

I will describewith reference to the ac companyingdrawing various apparatus in accordance with this invention but I do not limit myself to the precise arrangements 'and connections described and illustrated.

Figs. 1, 2 and 3 illustrate diagrammatically different embodiments .of my invention. Y

' Fig. 4 is a-sectional view of a transformer formmg part of my invention, and

Fi 5 illustrates dia mlnatically a modl cation of the embo irnent shown in Fig. 3.

ig. 6 illustrates a container for the transformer.

' (ii iii The derivatives or ratios and W can be easily, determined by experiment. They are given by the curve of the grid current as a function of u for a given potential V on' the plate and by the curve of the grid current as a function of V for a given potential v in the grid. The inverse or reciprocal of these derivatives has the dimen- 810118 of a resistance. Thus: 7

(it e 1 W o C. LATOUR,

' Referring to the drawing the thermionic relay 1, comprises a plate 2, a grid 3' and a filament 4 which may be rendered highly incandescent by a battery 5 (Figures 1 and 2). Between the plate and one terminal of the filament (the negative terminal for example) is connected battery 6, either directly through a resistance 7 (Figure 1) or through the primary coil of a transformer 8 the secondary coil of which is connected with a resistance 7 as shown in Figure 2.

The gridand the filament are connected on the other hand, either directly or through the agency of a transformer,- to the terminals of the source containing the small electro-motive force to bedetected. r

In the following description i have set forth the equations for the grid current and the plate current in the case of aninfini eiy small alternating voltage introduced into the grid filament circuit. These equations are indispensable in order to rationally carry out the construction of: the amplifiers with lamps;

The potentials V on the plate and 0-. on the grid may be stated with relation toone terminal of the filament for example the Under these conditions equation (1) can be written thus:

The current I in the plate is in its turn a 95 funct on of -V and of c. Thus I=f (V, o); ,What has been said on the subject of mm rent 2' may be repeated for I. At any point defined by the. same continuous potentials V,- and v on the plate and on the we have:

'd and corresponding to a current I, on t e plate (11 The derivat ves or iatios W and a?) can be easily determined by ex eriment. They are given by the curve of t 1e plate current as a function of V for a potentiol o on the grid and by the curve of the plate current as a function of v for a potential V on the plate. 7

The inverse or reciprocal of these derivatives or ratios has again the dimensions of a resistance. Thus:

(ZI 1 1 dV V=V., 1' do v=.v -r, Equation (2) can be written under these circumstances as follows:

( IO)= "fi The first term is necessarily zero since for the point of. operation consldered, we have,

b h othesis y yp E-I.,R=V.,

We therefore arrive at the equation:

U-l- J R20 If we suppose that the resistance R is inserted together with the insertion of a perfect transformer (i. e. one having no magnetizing current, and capacity of windings zero, no leakages. and no losses) we arrive at the same equation. The fall of pressure caused by the transformer is, in effect, due to the circulation in the resistance R of an alternatingcurrent K J, denoting by K the ratio of transformation 'of the transformer in the step down direction.

We have therefore In the case of the transformer the only difference that exists is that the voltage E of the battery corresponds to the tensionor voltage V at the plate.

By placing the resistance R in all cases directly in the circuit of the lamp'the fundamental equations for the lamp become:

'u. -U 1ft (11) ll 2 J 's T4 U +JR 0 If the resistance R is purely non-inductive the vectors 7', u, U and J are necessarily in phase and the system of equation II) corresponds to the following system:

'8 J 's R) u lVe shall call the relay-effect the ratio between the energy liberated in the plate filament circuit with a resistance R and the energy furnished and consumed in the grid filament circuit. The relay effect corre- There is a value of R which will be denoted by R optimum which gives a maximl -lrlill value for the relay effect R (optimum) Q 3 If av transformer be employed such a transformer should be chosen having a ratio of transformation K such that -On the other hand it is found, by referring to equation (III) that the apparent resistance Y of thegrid, filament circuit'is If the source which contains the tension or voltage to has an impedance Z it will be nec-..

essary to employ, in order .to supply the grid-filament circuit, a transformer the transformation ratio of which in the step up direction will be such that In this way the maximum power can obtained from the source. Care will {have to be taken that the capacity of the secondary winding of the transformer b'e'such that, for the frequency of current considered, it does not tend to short circuit this winding b closing it across a capacity smaller than 1. His supposed in. the foregoing description that the capacity represents an impedance considerably greater than Y We have thus determined with precision the ratios of transformation to be adopted in transformers as used for thermionic reays.

With regard to the constitution of the transformers themselves the theoretical conditions above indicated will be approached.

(1) By using asufficient mass of iron and sheets of high permeability forthereduction of the magnetizing current.

(2) B inserting the primary and secondary win ings one in the other (for example by using a primary coil enclosed half way in the secondary winding or conversely) so as to reduce leakages. l 1

(3) By usin sheets of silicon of reduced thickness or o iron melted in vacuo for the reduction of losses. a x

(4) B reducing the capacity of the windings with relation to the mass.

. (5) By reducing'the distributed capacity of the winding by causing the 'product'of length of the wires formin the primary and secondary windings .to be as small as possible. v The object'of the .last precaution is to avoid the distortion of the word when a telc phonic amplifier is employed.

In the; case of hi h frequency currents the primer and secon ary coils may be formed .of a p urality of successive layers several millimetres apart for the purpose of reducing the capacity between the layers. Coils in several strata will thus be obtained. Each stratum may consist of two layers of similar wire arranged in parallel to reduce theresistance of the winding without increasing its capacity.

Fi are 4 shows-one of the forms that may be a opted for the construction of the transformers. In this form, as will be seen, the

magnetic circuit adopted comprises threebranches: a middle-branch around which are placed the primary and secondary coils, and two side branches through which the flux winding,

But the cross sections 0 the magnetic circuit at b and 0. may bemade as great as the cross section at a, or even greater, so as y to reduce as far as possible the value of the induction in the lparts of the magnetic circuit external to t e'coil. -By this the losses are considerably reduced: they substantially no longer occur except in the part of the magnetic circuit located inside the windings. The shape of the transformer thus becomes somewhat unusual. The qualit employed is of course that which gives the minimum losses by Foucault currents and hysteresis. The manner in which the wind ings arearranged has also been illustrated in the figure. The rimary is represented )2 and Z which constitute the secondary the'coils X and Z being connected in series. In this way the ma etic leaka between the primary and secon ary is great y reduced. A suitable distance e is left between the windings and the ma netic circuit in order to reduce the capacity tween this circuit and the windings.

tions may be solved by imaginary quantities of plates the coil Y sandwiched between the coils l In equation (2) it has been first supposed I that the resistance R was non-inductive but by treating a, j, V and J as vectors capable p of a certain displacement of phase between them. This case corresponds tothat in which ed for examplewith a telep one receiver. I the resistance and of the capacity per unit of the ap' aratus is provi The workin resistance above considered may obviously constituted by the grid filament circuit of a second lamp which will act in its turn on the working resistance proper.

This is shown in Figure 3 in which the The ratio of the transformer is determinedby the value of R optimum and of Y. 'K. R.

optimum will be made equal to Y.

It will be noted that the utilization of one and the same batte arrangement shown in Figure 3, with the is effected without coma plications of a special kind 'acoordin to the proviso that the resistance of the battery be negligible.

The source which supplies the transformer T may be a circuit comprisin a battery and a microphone and an amp cation my p 115 rst transformer is de'ten transformer T that rapidly becomes zero for 'v negative ifc zO. In this latter case the mean obtained will therefore be the double of the,

mean for the timeduringwhichw remains positive, which mean can be casily'app'reciated by the curve of the rid current. This mean being determined t e reciprocal thereof will be taken to determine the resistance 7-,.

In reality it is convenient to take accountof the harmonic developed by the variable character of T Distortion might result therefrom. This will be reduced by keep:

'ing within the bounds of a-lower ratio of transformation for the transformer T,. For the purposes of speech, what will be lost in intensity will be gained'in clearness.

It is known that the weakening in intensity of an alternating current that is being transmitted alongl a telephone line is greater according. as t e frequency of the current is higher. It is for this reason that in telephone lines of a certain len h the high-frequency harmonics of the te ephone current are absorbed by the line. There results fron this a distortion of speech at the receiving end. This distortion may be counterbalanced by promotin the amplification .of these harmonics at t e transmitting end and at the receiving end.

It is possible in an amplification at the transmitting end to seek to forestall the deformation introduced by the telephonic line by setting up in anticipation a. deformation 'in .the opposite direction by artificial arrangements in the primary circuit of the An elementary arran ment consists 1n shunting for example t e rimary coilsof the transformers by a self induction or choke-coil or by constructing these transformers with a heavy magnetizing current. In this way the high frequency currents will be favoured relatively to those of low frequency which will tend to be short circuited; the harmonics will stand out better and the damping action of the line will have a less injurious efiect.

It is possible, in an amplification at the receiving end to attempt in like manner to restore the form of the word and to neutraliz'e the distorting action of the line. An elementary arrangementwould again be to supply the primary 0011 of the transformer T, with the insertion of a small capacity which would allow preference of passage to currents of higher frequency or harmonics.

The arran ement of the capacity may extend to al the transformers in succession. In place of a capacity a damper may be em loyed (composed of a self induction coil an a capacity in. shunt) which will be obtained by having a greater impedance for the low frequencies.

Arrangements of this kind are illustrated by way of example in Fig. 5, in which the connections are similar to those shown in Fig. 3, the modifications referred to above consisting in the insertion of small capacities 9 in the circuits supplying current to the transformers T and T respectively. Either or both of these capacities may be shunted by a self-induction coil tuned so as to have a greater im edance for low frequencies, one such coil eing shown at 11 in the circuit' connected to the transformer T In any way it can be seen that by an amplification at the outset and at the receiving end it is possible to compensate the ilistortion introduced by the transmitting The same apparatus shown in Figure 3 may serve for amplication at thev transmitting end and for amplification at the receiving end by the action of a sim le commutator which will substitute the line circuit for the microphonic circuit and the telephone circuit for the line circuit. The micro honic circuit might utilize as a battery tlie local battery used for heating the filament or a battery P In the receiving position the current will be out upon the microphone.

It is possible also while transmitting and receiving to change, if nry or desired,

'the ratios of transformation of the transformers T and T A similar apparatus would allow each subscriber of a telephonic system to effect communication individually at long distance away.

In order to reduce the relative'importance of the disturbing currents a high resistance may be used which would restore the audie bili'ty of the word to a normal value by considerably reducing the superfluous noises.

A particular phenomenon which is produced in the thermionic relays is that of singing or .howling due to static phenomena. This may be prevented by pro rly defining the potential of the cores of he transformers and if necessary, that of their windings as well as that of the primary coil of the transformer T with relation to the battery'P. To this end, it sufiices to connect the above mentioned masses which may be represented by M M, M and a primary termlnal of the transformer T to any point of the battery P, either to the positive pole or the negative pole or to an intermediate cell as shown in dot and dash lines Figure 3.

In the particular case in which the workless signals an ing resistance R is a telephone receiver and in which it is desired to avoid too great a difference of potential between the winding of the telephone and the mas, the potential of the positive pole of the battery will be chosen as the potential of the mass.

In like manner the core of the windings of the transformers (always more particularly of the transformer T might have its .potential defined. V

Itmight be found advantageous in certain .cases' tofarranga-the transformers in conductivef'casings (see Figl'o) such as co per or aluminum by the known method 0 Faradays' cage in orderto avoid magnetic leakage from one transformer .to the other and at the same time to define their static potential. This arrangement will be particularly interesting in the. case of the aperiodic reception at high frequency.

This remark refers to thecase in which, in conformity with what is provided by the invention, there is established for reception in wireless telegraph an amplification of the high frequency c rent received by the antenna by meansof iron transformers as it were a matter of a low-frequency current. In this case one can refrain from establishing special syntony with capacity on the primary or secondary circuit of. above mentioned transformers forthe frequency of the current received which eliminates the adjust-- ments in the am lifying system.

Having fully escribed my invention, what I claim as new and desire to secure by Letters Patent, is

1. In an amplifying apparatus for wirethe like, a thermionic relay comprising an evacuated bulb, a plate, a filament and a grid in said bulb, and a transformer having a-core of-laminated iron and two windings of relatively low capacit arranged coaxially one to the other, one of said windings being in circuit with said )late and filament, the transformation ratio 0 said transformer being a function of the value of the imaginary impedance which, if inserted in the plate filament circuit, would give rise to the maximum relay effect.

2. In an em less signals an the like. a. thermionic relay comprising an evacuated bulb, a plate, a filamentand a grid in said bulb, and "a transformer having a. core oflaminated ilLOn and two windings of relatively low capacit .arranged coaxially one to the other, one 0 said windings being in circuit with said grid and filament, the transformation ratio of said transformer being a function of the value of the imaginary impedance-which, if insertedin the grid filament circuit, would give rise to the maximum relay effect.

3. In an amplifying apparatus for wireless si 9.15 and the like, a thermionic relay comprising an evacuated bulb. two electrodes lifying apparatus for wirchaving a laminated iron core and two windings of relatively low capacity arranged coaxially one to the other and comprising each a plurality of layers of conductors connected in parallel, one of said windings being inserted in one of said circuits, the transformation rat-io'of Said transformer being a function of the value of the. imaginary impedance which, if inserted in the latter circuit, would give rise to the maximum relay effect.

4. In an am lifying apparatus for wireless signals and the like, a thermionic relay, a transformer having a winding connected therewith, a magnetic metal core for said transformer, and means for defining the potential of said core.

5. In an am lifying apparatus for wireless signals an the like, a thermionic relay, a transformer having a winding in circuit therewith, a magnetic metal core for said transformer, and means for defining the potential at one point of the winding of said transformer which is not in circuit with said relay.

' 6. In an amplifying apparatus for wireless signals and the like, a thermionic relay,

therewith, a magnetic metal core for said transformer, a source of current, and a connection between said metal core and source of current.

7. In an amplifying apparatus for wireless signals and the like, a thermionic relay.

said transformer being in circuit with said relay, the other winding of said transformer being connected withsaid source of current, and the core of said transformer being connected with said source of current.

8. In an amplifying apparatus for wireless signals and the like, a thermionic relay comprising an evacuated bulb, a plate, a filament and a grid in said bulb, a transformer, a magnetic metal core for said transformer, a source of current, said source of current and one winding of said transformer being in circuit with said plate and filament, and a connectionbetween said core and one terminal of said source of current.

9. In an am lifying apparatus for wireless signals an the like, a thermionic relay comprising an evacuated bulb, a plate, a filament and a grid in said bulb, a transformer, a magnetic metal core for said transformer, one winding of said transformer being in circuit with said filament and grid, a source of current in circuit with said plate and filament, and a connection.

between said core and one terminal of said source of current;

10. In an amplifying apparatus forwireless signals and the like, a plurality of thermionic relays comprising each an evacuated bulb, a plate, a filament and a grid in said bulb, transformers having one of their.

windings in circuit with the filament and grid of each of said lamps respectively, a magnetic metal core for each of said transformers. acommonsourceof current in circuit with the plate and filament of each of said relays, and connections between said source of current and the core of each of said transformers.

11. In an amplifying apparatus for wireless signals and the like, a plurality of thermionic relays comprising each an evacuated bulb, a plate, a filament and a grid in said bulb, transformers having one of their windings in circuit with the filament and grid of each of said lamps respectively, the other'winding of one of said transformers being adapted to be connected to a source of potential, a common source of current in circuit with the plate and filament of each of said relays, and a connection between said source of current and the transformer winding adapted to be connected to a source of potential.

12. In an amplifying apparatus for wireless signals and the like, a thermionic relay, a transformer havin two windings arranged one within the other and an iron core therefor, one of said windings being in circuit with said relay, said transformer beingadapted to operate with high frequcnc currents. 7

13. In an amplifying apparatus for wireless signals and the like, a thermionic relay, a transformer having one winding in circuit with said relayjand an iron core therefor, said core comprising two side branches and a central branch connected at their ends, the two windings of the transformer being 7 arranged one within the other and aroun line. to promote the amplification o the central branch of the core, the cross sectional area of each of the side branches being at least equal to that of the central branch.

14. In an ampiifying apparatus for wire- I less signals-and the like according to claim 1, means whereby the transformer provides a deformation of a telephone/current in opposition to the deformation provided b the the high frequency currents in telephonic transmission, and correct the distortion of speech at the receiving end.

15. In an amplifying apparatus according to claim 1, forthe telephonic transmission of wireless signals and the like, a thermionic relay having means for promoting the am-' plification of-the high frequency harmonics at the transmitting end, to counter-balance the distortion of speech due to the weakens ing in intensity of the alternating current.

16. In an amplifying apparatus for the telephonic transmission of wireless signals and the like, a thermionic relay in which a transformer has means for neutralizing the distorting action of the .line by an amplification of the high-frequency harmonics of the telephone current and for counter-balancing the distortion of speech at the receiving end.

17. In an amplifyingapparatus for wireless signals and the like, a thermionic relay, a transformer having two .win arranged coaxially one tothe other, an iron core therefor one of said'windinggbeing in i'ircuit with said relay, and a. conductive casing for said transformer in order to avoid' magnetic leakage and to define potential of the transformer.

. In testimon whereof I afiix my signature in presence 0 two witnesses; p

the static MARIUS o; A. LkToUR. 

